Classifier rake lifting mechanism



Sept. 5, 1933. s. I. B'ousMAN 1,925,513

CLASSIFIBR RAKE LIFTING MECHANISM V Original Filed Oct. 21, 1930 3 Sheets-Sheet 2 gwoanl ob III/I'll YIIIIIIIIIIIIIIIIIIL VII II 'IIIIII////////I//I// Sept. 5, 1933 s. a. BOUSMAN CLASSIFIER RAKE LIF'IING MECHANISM Original Filed 'Oct. 21, 1950 s Sheets-Sheet 3 ii/swan Baas/W40,

Patented Sept. 5, 1933 PATENT OFFICE I 1,925,518 CLASSIFIER RAKE LIFTING MECHANISM Samuel I. Bousman, Denver, 0010., assignor, by

mesne assignments,

to The Dorr Company,

Inc., New York, N. Y., a corporation of Delaware ' Application October 21,

1930, Serial No. 490,147

Renewed May '18, 1932 7 Claims.

This invention relates to improvements in classifiers of the type employed to separate solids suspended in liquids.

In classifiers of this type, the feed of finely divided solids suspended in liquid is introduced into the tank havinga sloping bottom, the finer solids overflowing with the liquid while the more rapidly settling solids collect on the bottom and are raked or conveyed upwardly to a dischargepoint above the liquid level by means of a reciprocating raking mechanism. This raking mechanism includes a series of rakeswhich, in order to operate efliciently, must have a rectilinear movement during their forward or feed stroke adjacent the classifier bottom, followed by an upward and then a return movement. In other .words, the rakes follow a path which may be described as a D-motion, if the D be turned down on its face.

One object of this invention is to devise means for raising the rakes away from. the bottom of such a classifier to inspect, repair or renew the rakes. Also when the classifier is shut down, the rakes have to be elevated out of the sludge being treated because if this were not done, the

sludge tends to solidify onto and between the rakes. This makes restarting a difficult operation. If the rakes are lifted out of the sludge, thereis no undue starting load or strain for they can be lowered into the sludge gradually after their reciprocation has been begun.

Another object of this invention is to so arrange the end of the classifier tank, that mud banks will not form thereon because heretofore, this trouble has been encountered. Such mud banks build up on the classifier end until they are dislodged by their own weight and fall in chunks into the classifier bath. And such chunks are detrimental to the functioning of the classifier blades, in fact sometimes a blade is broken off by sucha chunk. At the same time the end has to be so devised as to offer no interference to the rake lifting operation. I

The invention resides in mechani complishing these objects and also in the arrangement and combination of parts shown and described herein.

For illustrative purposes, I have accompanied this specification with drawings of one embodiment of my invention in which i Figure 1 shows a side elevational view of a classifier having embodied therein the features of this invention.

Figure 2 shows a plan view thereof.

sms for ac- Figure 3 shows a plan view thereof.

Figure 4 shows an elevational view of the rake lifting apparatus while Figure 5 is a perspective view of the same apparatus.

The classifier proper is provided with an inclined bottom, 11, in a tank 12, having an inclined end E to which tank the pulp to be stratified or classified is fed through launder 13 and the cleaned sand exits at 13a.

Adapted to be reciprocated in the tank, is a rake mechanism 14, comprising longitudinal frame members 15 carrying depending therefrom, a plurality of rakes or raking blades 16.

The raking mechanism is supported by a pair of hangers 17 at its upper or front end and another pair of hangersv 18, at its lower orrear end, all of the hangers being secured to the frame members 15. i

The frame members 15, and their rakes 16, are in effect a unit which is first moved parallel to the inclined bottom 11, upwardly away therefrom, backwardly and then downwardly to begin the cycle anew. The path of movement is substantially that of the letter D turned on its face. Y

Means for causing this reciprocation are provided through the various shafts, levers, eccentrics and bell-cranks shown but as they form no part of this invention, they will not be described other than'to say that the rear hangers 18 are supported from a shaft 19. Rotatably mounted on shaft 19, is a link 2o, operated by a bell-=crank 2i, pivoted at 22. Bell-crank 21, is motivated by reach rod 23, forming a part of the rakeactuating mechanism.

The rake-lifting mechanism comprises a lever or link 24, on which at 22, is mounted the bell crank 21.. The link 24, is keyed upon rotatable shaft 25, supported on a bracket 26, carried by suitable support 27. Also keyed to shaft 25, is an upwardly curved yoked arm 28, terminating in bearings 29, for rotatably supporting an idler drum 30.

Another drum 31, which is driven, is rotatably held in a bearing bracket 32, carried by support 27. The driven drum 31, is formed with differential sections or portions 33 and 34, with section 34 having a larger diameter than section 33. Drum 30 has a diameter intermediate between the two. Drums 30 and 31 in practice, are grooved to facilitate the neat and proper placing of the wraps thereon of the wire-rope or'other suitable flexible cables 35 and 36 which operate upon the The object of this drum-arrangement is to draw idler drum 30 toward the power drum Si,

the movement of which rotates yoked arm 28, shaft 25 and link 24. This in turn raises the shaft 22, on which bell-crank 21, is carried which further operates to move link 20 longitudinally of itself (or to raise it), whereby hanger l8 and the rake mechanism is thereby raised. To that end, cable 35 passes over the,top of drum 30 and has one end thereof secured to idler drum 30, at 37 and then takes around the top of the smaller section 33, of power drum 31, where it is secured thereto as at 38. Cable 36,passes from the bottom of the larger drum section 34, and has one end secured thereto as at 39, from whence it takes around the bottom of the idler drum 30, and its other end is secured to the idler drum as at all. I

Power drum 31 is driven preferably from the same motor which drives the classifier through any suitable linkages, or under certain conditions, it may be sufficient to have the drum 31, rotated by hand by means of a crank with a pawl ll and ratchet l2 which elements have been omitted from the drawing in Fig. l.

The end E of the classifier tank instead of lying all in one plane, as heretofore, has a break 41 in it formed by the junction of two portions 42 and d3 of the end, one sloping away from the break 41 in one direction and one sloping away in another direction. The lower end portion 42 is at substantially right angles to the bottom 11 of the classifier, or inclines outwardly from the perpendicular, while the upper end portion 43 inclines inwardly from the'perpendicular.

The upper inwardly inclined portion 43 terminates in an overflow weir l4 which is adjustable as to height, being composed of removable battens or strips 45 held in place between cleats 46 car ried by the side walls of the classifier tank.

With the various elements in the position shown in Figures 2 and 3, the rake mechanism is in operative relationship to the inclined bottom 11, or the classifier. Suppose now it is desired to lift the rake mechanism to inoperative position. In doing so, the upper or forward end is not raised but the whole rake mechanism 14 is rotated about the pivotal support or the front hangers 17. In other words, the rear or lower end only of the rake mechanism is lifted.

Power, therefore, is applied to drum 31, in the direction of the arrow, namely, anti-clockwise. This rotation of drum 31, winds up cable 36, upon large i section 34, faster than it unwinds from idler drum 30, whereupon drum 30 is drawn to ward drum 31, which results, as explained above, in the rake mechanism being raised. In raised position, with drums 30 and 31, near together, cable 35, has been wound upon drum 30. To lower the rakes by moving the two drums apart, drum 31 is rotated in clockwise direction, whereupon, because of the weight of the various depending parts idler drum 30, is given an impulse which rotates it similarly in a clockwise direction, and because drum 30 is larger in diameter than drum section 33, cable 35, unwinds therefrom faster than it winds up on drum. section 33, drum 30 moves away from drum 31, to lower the rakemechanism to normal operative position. When cable 35 is under tension, cable 36 is returning idle to position and vice versa.

It will be seen that I have devised a simple but powerful means for raising and lowering the classifier rake-mechanism toward and away from the classifier bottom. Also it is so arranged that aet tia it does not interfere with the rake-actuating mechanism and can be operated therewith independently or synchronously. By constructing the end E of the classifier tank 12 in accordance with this invention wherein the upper portion 43 is inclined inwardly and away from the vertical, it is found that this inclination inwardly prevents flnes'irom building up in the form of mud banks on the classifier end. By interposing the outwardly inclined portion d2 between the classifier bottom 11 and the upper end portion 43, space is provided for the necessary reciprocation of the classifier raking mechanism 15. If the upper end portion 4:3 were continued downwardly in its same plane to meet the inclined bottom 11 of the classifier, a sharp corner would be formed in which solids would build up and interfere with the proper functioning and reciprocation oi the classifier rakes. At the same time there might be ofi'ered interference between the inwardly inclined end to the rake when they are lifted or raised by the rake lifting mechanism above de scribed. By the construction shown ample room is provided for the lifting of the rakes and at the same time formation of mud banks on the classifier end is eliminated.

I have shown the preferred embodiment of my invention but it is obvious that modifications thereof and other embodiments may be made without departing from the spirit and scope of the invention.

I claim:

I 1. A device of the class described having a pulp receiving tank provided with an inclined bottom,

' rake structure adjacent said bottom, mechanism for reciprocating said rake structure, and means for raising and lowering said rake structure with respect to said inclined bottom comprising a movable element capable of pivotal movement from which a part or said rake structure is supported, a rotatable drum, a pivoted support for said drum whose pivotal movement controls the pivotal movement of said movable element, a drum, and a flexible connection arranged between said drums whereby one may be moved toward and away from the other to raise and lower said rake structure respectively.

2. A device of the class described having a pulp receiving tank provided with an inclined bottom, rake structure adjacent said bottom provided with hangers, mechanisms for reciprocating said rake structure comprising linkages and bell cranks associated with said hangers; and means for raising and lowering said rake structure comprising a pivoted arm supporting said bell crank. a support associated with said arm and pivotally movable therewith, a rotatable drum mounted on said support, a second drum, and a flexible connection arranged between said drums whereby one drum may be moved toward and away from the other to pivotally move said pivoted arm and said support which in turn raises and lowers said lid 5. The apparatus according to claim 3 in which said drums have different diameters.

' 6. Theapparatus according to claim 3 in which one drum has a plurality of portions of different diameters.

7. The apparatus according to claim 3 in which said flexible connection comprises a cable with one end secured to'one drum and the other end secured to the other drum.

SAMUEL I. BOUSMAN. 

